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Arnoldsally

Member Since: 30 Oct 2019
Location: Derby
Posts: 8

Interference to radio

Hi all, my 2003 TD5 Defender has been running very well since I purchased it 4 years ago and I am really pleased with it.
I service it and treat the underside with XCP twice a year to keep rust at bay.

I am a radio ham and recently installed a ham radio, I followed all the advice that I was given which was loads but it has a bad case of interference that 50% of the incoming signal is missing.

I have bonded everything, moved the antenna etc etc and still the same. I now think its the alternator as when I turn the key to dash lights only the interference is there and once the car is running its terrible.

Has anyone had this and if so what did you do please.

thank you

Patrick

23rd Nov 2022 8:19pm

custom90

Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20441

All I can think of is EMF, so you can use some foil or shielding wrap where you can.
High current motors, LED lighting in particular headlights or LED light bars can all cause interference and USB power sources.
All that can be done is use quality aerial / antenna cables, shield it all all and make sure you have good grounds that you have done. $W33T $0U7H3RN $UG4R
🇬🇧🏴󠁧󠁢󠁥󠁮󠁧󠁿🏴󠁧󠁢󠁷󠁬󠁳󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿🇮🇪🇺🇸⛽️🛢️⚙️🧰💪

23rd Nov 2022 9:19pm

Arnoldsally

Member Since: 30 Oct 2019
Location: Derby
Posts: 8

Thank you custom90steve, tried it all and I have no LEDs as they are a known problem to ham equipment and they are not allowed in the house lol.
Most sites are saying fit a suppressor to big items like the alternator but getting to it is another thing.

Patrick

23rd Nov 2022 9:32pm

custom90

Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20441

Have you tried ferrite chokes? Alternator whine can be an issue, but realistically the only thing you can think about to do with that is change alternator.

I know what you mean with Alternators, they are often a pain to get near. $W33T $0U7H3RN $UG4R
🇬🇧🏴󠁧󠁢󠁥󠁮󠁧󠁿🏴󠁧󠁢󠁷󠁬󠁳󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿🇮🇪🇺🇸⛽️🛢️⚙️🧰💪

24th Nov 2022 9:08pm

Arnoldsally

Member Since: 30 Oct 2019
Location: Derby
Posts: 8

Ebay is fed up of sending me ferrite cores, the Defender is full of them. If the weather is ok I am going to pull a fuse to see if it stops the noise and then work thro all the others too.

24th Nov 2022 9:25pm

custom90

Member Since: 21 Jan 2010
Location: South West, England.
Posts: 20441

Might be worth doing a continuity check on the Antenna cable, possible break internal or replace.

I agree with ferrites, I found Alu shielding was more effective.

Antennas and reception can be the most annoying thing, the most annoying thing to me is having to gain access to it and the cable. $W33T $0U7H3RN $UG4R
🇬🇧🏴󠁧󠁢󠁥󠁮󠁧󠁿🏴󠁧󠁢󠁷󠁬󠁳󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿🇮🇪🇺🇸⛽️🛢️⚙️🧰💪

24th Nov 2022 10:57pm

Arnoldsally

Member Since: 30 Oct 2019
Location: Derby
Posts: 8

Re: Interference to radio

Arnoldsally wrote:
Hi all, my 2003 TD5 Defender has been running very well since I purchased it 4 years ago and I am really pleased with it.
I service it and treat the underside with XCP twice a year to keep rust at bay.

I am a radio ham and recently installed a ham radio, I followed all the advice that I was given which was loads but it has a bad case of interference that 50% of the incoming signal is missing.

I have bonded everything, moved the antenna etc etc and still the same. I now think its the alternator as when I turn the key to dash lights only the interference is there and once the car is running its terrible.

Has anyone had this and if so what did you do please.

thank you

Patrick

Just to say thank you for all the advice.
I used ferrite core on everything but the the biggest interference was from the USB connector pushed into the fag lighter, cannot believe it but ferrites sorted that, thanks all.

13th Feb 2023 8:20pm

Intercept

Member Since: 27 Feb 2017
Location: Suffolk
Posts: 587

2002 Defender 110 Td5 Black LE Java Black

Arnoldsally wrote:
the biggest interference was from the USB connector pushed into the fag lighter

Those things are nasty - whilst it would be simple enough to use a 7805 linear regulator and a couple of capacitors to drop the 12ish/14.4V to 5V for the USB instead most use a cheap switched-mode DC/DC converter to reduce the current drain whilst the engine is off. These produce a ton of RF hash due to their poor suppression - hence the need for aftermarket ferrites.

14th Feb 2023 4:35pm

Arnoldsally

Member Since: 30 Oct 2019
Location: Derby
Posts: 8

Thank you Intercept, they are dirty and my ham radio equipment was suffering badly with them.

14th Feb 2023 10:09pm

sako243

Member Since: 08 Jul 2014
Location: Wales
Posts: 1223

1994 Defender 110 300 Tdi CSW Alpine White

Re: Interference to radio

Arnoldsally wrote:
I am a radio ham and recently installed a ham radio, I followed all the advice that I was given which was loads but it has a bad case of interference that 50% of the incoming signal is missing.

When you say 50% is missing what on earth do you mean?

Have you done something as basic as test the match on the aerial to your base unit? If the antenna match is off then no point in trying to chase anything else first. Ed
82 Hotspur Sandringham 6x6
95 Defender 110 300Tdi

15th Feb 2023 8:10am

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